AWAKE Run 2bc Spectrometer

Wednesday 31 Jul 2024, 13:30 → 14:30 Europe/Zurich

6/2-008 (CERN)

31072024espec_meeting.pdf

Present: Matthew Wing, David Cooke, Fern Pannell, John Farmer, Marlene Turner, Collette Pakuza

 

Discussion points:

• Magnet settings during operation: DC prepared comprehensive GUI that shows imaging and focusing positions in the x/y planes as well as an acceptance (energy, position and angular) for given settings. GUI can be used in the control room. No adjustments of the quad settings are needed when changing plasma length (when using plungers). It is better to underfocus rather than overfocus.
  
  • To do: DC upgrade to also include correlated beam settings to understand tilted beams (lower priority).
• New camera array GUI: currently working well with single images (and BG subtracted projection). Difficult operationally to switch between cameras. Suggestion to combine all images into one. Online waterfall plot now has also energy available on the horizontal axis.
  
  • To do: FP to do before the next run and check whether the BG subtraction should be done similarly to the old GUI.
  • To do: FP Complete stiching of all cameras
• Old spectrometer GUI: DC: difficult to understand the code, was easier to rewrite the GUI. BG subtraction now based on model data and a fit to the image (excluding the signal region) --> works well, also calculates accelerated charge correctly.
  • To do: DC add this GUI to the AWAKEOP CCM.
• Agreement of e-beam ICT measurements with spectrometer. FP: more data is needed.
  • To do: FP to take more data during the week of the 5th of August and present at a future meeting.
• CLEAR data analysis --> To do: FP, DC to present at a future meeting.
• Run 2c spectrometer: MT: EG had discussions with Gilles le Godec, prepared him for further needs. Should design the spectrometer system we need. Only limitation may be that we need to use old magnets.
  • To do: MT to check with Eloise and Alena on the available space for Run 2c.
  • To do: DC to check the footprint of the triplet design.
  • To do: DC to also investigate the size of a possible dogleg (as suggested in the review)
• The energy discrepancy between the new and old camera systems have been resolved by refining the start and end position of the screen (changing ROI).
• Spectrometer cameras 5-7 do not have a saving issue, however the image of camera 5 looks visible different.
  • To do: FP to put the injection beam into the region overlapping two cameras.
• Moving the expansion volume screen while the proton beam is one must be avoided (same as for BTV54), becauses it triggers reboots in many cameras.
• Aperture of the HiRes Camera is now fully open --> more light
  • To do: FP to compare how much more, since lens does not have f# markers.
• It was seen that the turning the quadrupoles on steers the ebeam. Big difference for on/off. Negligible difference when only changing the current. Negligible difference when setting the dipole current. Consequently, magnets are now set to their expected values for the day before beam alignment.